<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgpu - logarithmic depth buffer</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="example.css">
		<style>

			body{
				touch-action: none;
			}

			.renderer_label {
				position: absolute;
				bottom: 1em;
				width: 100%;
				color: white;
				z-index: 10;
				display: block;
				text-align: center;
			}

			#container {
				display: flex;
			}

			#container_normal {
				width: 50%;
				display: inline-block;
				position: relative;
			}

			#container_logzbuf {
				width: 50%;
				display: inline-block;
				position: relative;
			}

			#renderer_border {
				position: absolute;
				top: 0;
				left: 25%;
				bottom: 0;
				width: 2px;
				z-index: 10;
				opacity: .8;
				background: #ccc;
				border: 1px inset #ccc;
				cursor: col-resize;
			}

		</style>

	</head>
	<body>

		<div id="container">
			<div id="container_normal"><h2 class="renderer_label">normal z-buffer</h2></div>
			<div id="container_logzbuf"><h2 class="renderer_label">logarithmic z-buffer</h2></div>
			<div id="renderer_border"></div>
		</div>

		<div id="info">
			<a href="https://threejs.org/" target="_blank" rel="noopener" class="logo-link"></a>

			<div class="title-wrapper">
				<a href="https://threejs.org/" target="_blank" rel="noopener">three.js</a><span>Logarithmic Depth Buffer</span>
			</div>

			<small>Mousewheel to dolly out.</small>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/webgpu": "../build/three.webgpu.js",
					"three/tsl": "../build/three.tsl.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three/webgpu';

			import { Inspector } from 'three/addons/inspector/Inspector.js';

			import { FontLoader } from 'three/addons/loaders/FontLoader.js';
			import { TextGeometry } from 'three/addons/geometries/TextGeometry.js';

			// 1 micrometer to 100 billion light years in one scene, with 1 unit = 1 meter?  preposterous!  and yet...
			const NEAR = 1e-6, FAR = 1e27;
			let SCREEN_WIDTH = window.innerWidth;
			let SCREEN_HEIGHT = window.innerHeight;
			let screensplit = .25, screensplit_right = 0;
			const mouse = [ .5, .5 ];
			let zoompos = - 100, minzoomspeed = .015;
			let zoomspeed = minzoomspeed;

			let container, border;
			const objects = {};

			// Generate a number of text labels, from 1µm in size up to 100,000,000 light years
			// Try to use some descriptive real-world examples of objects at each scale

			const labeldata = [
				{ size: .01, scale: 0.0001, label: 'microscopic (1µm)' }, // FIXME - triangulating text fails at this size, so we scale instead
				{ size: .01, scale: 0.1, label: 'minuscule (1mm)' },
				{ size: .01, scale: 1.0, label: 'tiny (1cm)' },
				{ size: 1, scale: 1.0, label: 'child-sized (1m)' },
				{ size: 10, scale: 1.0, label: 'tree-sized (10m)' },
				{ size: 100, scale: 1.0, label: 'building-sized (100m)' },
				{ size: 1000, scale: 1.0, label: 'medium (1km)' },
				{ size: 10000, scale: 1.0, label: 'city-sized (10km)' },
				{ size: 3400000, scale: 1.0, label: 'moon-sized (3,400 Km)' },
				{ size: 12000000, scale: 1.0, label: 'planet-sized (12,000 km)' },
				{ size: 1400000000, scale: 1.0, label: 'sun-sized (1,400,000 km)' },
				{ size: 7.47e12, scale: 1.0, label: 'solar system-sized (50Au)' },
				{ size: 9.4605284e15, scale: 1.0, label: 'gargantuan (1 light year)' },
				{ size: 3.08567758e16, scale: 1.0, label: 'ludicrous (1 parsec)' },
				{ size: 1e19, scale: 1.0, label: 'mind boggling (1000 light years)' }
			];

			init().then( animate );

			async function init() {

				container = document.getElementById( 'container' );

				const loader = new FontLoader();
				const font = await loader.loadAsync( 'fonts/helvetiker_regular.typeface.json' );

				const scene = initScene( font );

				// Initialize two copies of the same scene, one with normal z-buffer and one with logarithmic z-buffer
				objects.normal = await initView( scene, 'normal', false );
				objects.logzbuf = await initView( scene, 'logzbuf', true );

				// Resize border allows the user to easily compare effects of logarithmic depth buffer over the whole scene
				border = document.getElementById( 'renderer_border' );
				border.addEventListener( 'pointerdown', onBorderPointerDown );

				window.addEventListener( 'mousemove', onMouseMove );
				window.addEventListener( 'resize', onWindowResize );
				window.addEventListener( 'wheel', onMouseWheel );

			}

			async function initView( scene, name, logDepthBuf ) {

				const framecontainer = document.getElementById( 'container_' + name );

				const camera = new THREE.PerspectiveCamera( 50, screensplit * SCREEN_WIDTH / SCREEN_HEIGHT, NEAR, FAR );
				scene.add( camera );

				const renderer = new THREE.WebGPURenderer( { antialias: true, logarithmicDepthBuffer: logDepthBuf } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( SCREEN_WIDTH / 2, SCREEN_HEIGHT );
				renderer.domElement.style.position = 'relative';
				renderer.domElement.id = 'renderer_' + name;
				renderer.inspector = new Inspector();
				framecontainer.appendChild( renderer.domElement );

				await renderer.init();

				return { container: framecontainer, renderer: renderer, scene: scene, camera: camera };

			}

			function initScene( font ) {

				const scene = new THREE.Scene();

				scene.add( new THREE.AmbientLight( 0x777777 ) );

				const light = new THREE.DirectionalLight( 0xffffff, 3 );
				light.position.set( 100, 100, 100 );
				scene.add( light );

				const materialargs = {
					color: 0xffffff,
					specular: 0x050505,
					shininess: 50,
					emissive: 0x000000
				};

				const geometry = new THREE.SphereGeometry( 0.5, 24, 12 );

				for ( let i = 0; i < labeldata.length; i ++ ) {

					const scale = labeldata[ i ].scale || 1;

					const labelgeo = new TextGeometry( labeldata[ i ].label, {
						font: font,
						size: labeldata[ i ].size,
						depth: labeldata[ i ].size / 2
					} );

					labelgeo.computeBoundingSphere();

					// center text
					labelgeo.translate( - labelgeo.boundingSphere.radius, 0, 0 );

					materialargs.color = new THREE.Color().setHSL( Math.random(), 0.5, 0.5 );

					const material = new THREE.MeshPhongMaterial( materialargs );

					const group = new THREE.Group();
					group.position.z = - labeldata[ i ].size * scale;
					scene.add( group );

					const textmesh = new THREE.Mesh( labelgeo, material );
					textmesh.scale.set( scale, scale, scale );
					textmesh.position.z = - labeldata[ i ].size * scale;
					textmesh.position.y = labeldata[ i ].size / 4 * scale;
					group.add( textmesh );

					const dotmesh = new THREE.Mesh( geometry, material );
					dotmesh.position.y = - labeldata[ i ].size / 4 * scale;
					dotmesh.scale.multiplyScalar( labeldata[ i ].size * scale );
					group.add( dotmesh );

				}

				return scene;

			}

			function updateRendererSizes() {

				// Recalculate size for both renderers when screen size or split location changes

				SCREEN_WIDTH = window.innerWidth;
				SCREEN_HEIGHT = window.innerHeight;

				screensplit_right = 1 - screensplit;

				objects.normal.renderer.setSize( screensplit * SCREEN_WIDTH, SCREEN_HEIGHT );
				objects.normal.camera.aspect = screensplit * SCREEN_WIDTH / SCREEN_HEIGHT;
				objects.normal.camera.updateProjectionMatrix();
				objects.normal.camera.setViewOffset( SCREEN_WIDTH, SCREEN_HEIGHT, 0, 0, SCREEN_WIDTH * screensplit, SCREEN_HEIGHT );
				objects.normal.container.style.width = ( screensplit * 100 ) + '%';

				objects.logzbuf.renderer.setSize( screensplit_right * SCREEN_WIDTH, SCREEN_HEIGHT );
				objects.logzbuf.camera.aspect = screensplit_right * SCREEN_WIDTH / SCREEN_HEIGHT;
				objects.logzbuf.camera.updateProjectionMatrix();
				objects.logzbuf.camera.setViewOffset( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_WIDTH * screensplit, 0, SCREEN_WIDTH * screensplit_right, SCREEN_HEIGHT );
				objects.logzbuf.container.style.width = ( screensplit_right * 100 ) + '%';

				border.style.left = ( screensplit * 100 ) + '%';

			}

			function animate() {

				requestAnimationFrame( animate );

				// Put some limits on zooming
				const minzoom = labeldata[ 0 ].size * labeldata[ 0 ].scale * 1;
				const maxzoom = labeldata[ labeldata.length - 1 ].size * labeldata[ labeldata.length - 1 ].scale * 100;
				let damping = ( Math.abs( zoomspeed ) > minzoomspeed ? .95 : 1.0 );

				// Zoom out faster the further out you go
				const zoom = THREE.MathUtils.clamp( Math.pow( Math.E, zoompos ), minzoom, maxzoom );
				zoompos = Math.log( zoom );

				// Slow down quickly at the zoom limits
				if ( ( zoom == minzoom && zoomspeed < 0 ) || ( zoom == maxzoom && zoomspeed > 0 ) ) {

					damping = .85;

				}

				zoompos += zoomspeed;
				zoomspeed *= damping;

				objects.normal.camera.position.x = Math.sin( .5 * Math.PI * ( mouse[ 0 ] - .5 ) ) * zoom;
				objects.normal.camera.position.y = Math.sin( .25 * Math.PI * ( mouse[ 1 ] - .5 ) ) * zoom;
				objects.normal.camera.position.z = Math.cos( .5 * Math.PI * ( mouse[ 0 ] - .5 ) ) * zoom;
				objects.normal.camera.lookAt( objects.normal.scene.position );

				// Clone camera settings across both scenes
				objects.logzbuf.camera.position.copy( objects.normal.camera.position );
				objects.logzbuf.camera.quaternion.copy( objects.normal.camera.quaternion );

				// Update renderer sizes if the split has changed
				if ( screensplit_right != 1 - screensplit ) {

					updateRendererSizes();

				}

				objects.normal.renderer.render( objects.normal.scene, objects.normal.camera );
				objects.logzbuf.renderer.render( objects.logzbuf.scene, objects.logzbuf.camera );

			}

			function onWindowResize() {

				updateRendererSizes();

			}

			function onBorderPointerDown() {

				// activate draggable window resizing bar
				window.addEventListener( 'pointermove', onBorderPointerMove );
				window.addEventListener( 'pointerup', onBorderPointerUp );

			}

			function onBorderPointerMove( ev ) {

				screensplit = Math.max( 0, Math.min( 1, ev.clientX / window.innerWidth ) );

			}

			function onBorderPointerUp() {

				window.removeEventListener( 'pointermove', onBorderPointerMove );
				window.removeEventListener( 'pointerup', onBorderPointerUp );

			}

			function onMouseMove( ev ) {

				mouse[ 0 ] = ev.clientX / window.innerWidth;
				mouse[ 1 ] = ev.clientY / window.innerHeight;

			}

			function onMouseWheel( ev ) {

				const amount = ev.deltaY;
				if ( amount === 0 ) return;
				const dir = amount / Math.abs( amount );
				zoomspeed = dir / 10;

				// Slow down default zoom speed after user starts zooming, to give them more control
				minzoomspeed = 0.001;

			}
		</script>
	</body>
</html>
